Arrangements for use in the supporting of formwork for the casting of concrete slabs

ABSTRACT

A concrete slab-casting system includes props with heads beams extending between the heads and panels resting on elements slidable vertically on the beams. The elements can be locked in raised positions for the casting operation and lowered for removal of the panels one at a time. The joints between the beams and the heads permits removal of the beams without lowering the heads.

,ited Stats i 72] Inventor George B. A. Young Wheaton Aston, England [21] Appl. No. 773,821

[22] Filed Nov. 6, 1968 [45] Patented Oct. 19, 1971 [73] Assignee Rapid Metal Development Limited Aldridge, Walsall, Staffordshire, England [32] Priority Nov. 7, 1967, Feb. 26, 1968 [33] Great Britain [31 50567/67 and 9135/68 [54] ARRANGEMENTS FOR USE IN THE SUPPORTING 0F FORMWORK FOR THE CASTING 0F CONCRETE SLABS 8 Claims, 7 Drawing Figs.

1U.S. C1 249/18 E041g 11/52 [50] Field of Search 249/18, 20, 23, 28, 189, 26, 24, 25, 210,120

[56] References Cited UNITED STATES PATENTS 3,430,910 3/1969 Bowden 249/210 X 1,907,877 5/1933 Roos 249/28 X 3,239,188 3/1966 Gostling 249/18 X 3,294,357 12/1966 Tooley 249/23 X Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown Attorney-Holman & Stem ABSTRACT: A concrete slab-casting system includes props with heads beams extending between the heads and panels resting on elements slidable vertically on the beams. The elements can be locked in raised positions for the casting operation and lowered for removal of the panels one at a time. The joints between the beams and the heads permits removal of the beams without lowering the heads.

PATENTEUUCT 19 1971 I 3,614,048

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SHEET w 4 ATTORNLY ARRANGEMENTS FOR USE IN THE SUPPORTING OF FORMWORK FOR THE CASTING OF CONCRETE SLABS This invention relates to arrangements for use in the casting of concrete slabs.

The basic requirements of any system for use in casting concrete slabs are (a) form panels, (b) beams for supporting the form panels, and (c) props for supporting the beams.

Various arrangements have, in the past, been proposed for allowing the panels to be removed from the structure after the cast slab has partially set, leaving the slabs supported by the beams and props only. It has also been proposed to utilize arrangements whereby both the panels and the beams can be removed, leaving the partially set slab supported by the props only.

In prior proposals the removal of the panels or the panels and beams has been a somewhat hazardous procedure since it has been customary to employ arrangements whereby groups of the panels are released from contact with the under-surface of the slab simultaneously. There has thus been a danger of panels falling during removal thereof from the supporting structure with the possibility of injury to the workmen.

It is accordingly an object of the invention to provide a beam for use in supporting panels for the casting of concrete slabs in which this danger is avoided.

In accordance with this aspect of the invention there is provided an elongated beam adapted at its ends to be supported between props and having a form surface extending throughout its entire length, a plurality of panel-supporting elements independently slidably mounted on parts of the beam at spaced positions along the length thereof, locking means for supporting said panel-supporting elements in operative positions in which panels supported by sald panel-supporting elements will have their mould faces coplanar with the form surface of the beam, said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling panels supported, in use, by said panel-supporting elements to be removed after lowering thereof from the undersurface of the cast concrete slab, whilst leaving the form surface of the beam in supporting contact with the slab.

The invention also resides in the combination of the beam described above and props provided with beads which support the beam, in a manner such that two aligned beams can be supported at their adjacent ends by a single head with the form surfaces of said beams in coplanar relationship.

Conveniently the heads used on the props also have form surfaces and means are provided to enable release of the beams from the heads without releasing the heads from the undersurface of the cast concrete slab.

An example of the invention is now described with reference to the accompanying drawings in which:

FIG. 1 is a cut-away perspective view of an assembly for use in the casting of concrete slabs, the assembly comprising props, beams, and panels,

FIG. 2 is a side elevation of what is shown in FIG. 1,

FIG. 3 is an enlarged fragmentary section on line 3-3 in FIG. 2,

FIG. 4 is a section on line 4-4 of FIG. 3,

FIG. 5 is a detail of one end of one of the beams of the structure shown in FIG. 1,

FIG. 6 is an elevation of a head used on each of the props of the assembly shown in FIG. 1, and

FIG. 7 is a section on line 7-7 in FIG. 6.

As mentioned above the arrangement described makes use of panels 10, beams 11, and props 12 having heads 13.

The panels each have a mould surface 14 and a peripheral flange 15. The panels 10 are of elongated rectangular form and, as shown in FIG. 1, extend longitudinally between the beams 11 which are arranged in spaced parallel relationship.

Each beam 11 comprises an upper inverted channel shaped member 16 the web of which provides a form surface. The beam also includes a lower tension member 17 in the form of a flat metal strip the ends of which are bent up and secured to the channel 16 at the ends thereof. Rod lacings 18 extend between the channel 16 and the tension member 17 and are secured thereto to make the beam rigid. In addition there are a plurality of square section bars 19 extending between the channel 16 and the tension member 17 at positions spaced along the length of the beam. These bars 19 extend in directions perpendicular to the web of the channel 16.

Slidably mounted on the bars 19 respectively are a plurality of panel supporting elements 20. Each such element provides -a rectangular platform at the four comers of which there are projections 21.

For retaining the elements 20 in operative positions there is provided on each of the bars 19 a locking element 22. This locking element 22 is formed with a keyhole shaped aperture through which the associated bar 19 extends. The narrower portion of this keyhole shaped aperture 23 can be engaged with transverse grooves across the bar 19 at a position such that the locking element 22 supports the panel supporting element 20 at a position such that the distance from the platform of the element 20 to the form surface of the channel 16 is equal to the width of the flange 15 of each panel. When the narrower part of the keyhole slot 23 is disengaged from the grooves in the bar the element 20 can be lowered sufficiently to allow a clearance between the platfonn of the element 22 and the free edges of the sides of the channel 16 which is greater than the width of the flange I5.

Attached to each end of the channel 16 is a tongue 24 in the underside of which a recess 25 is formed. These tongues coact with the heads 13 in the mounting of the beams 11. As shown in FIGS. 6 and 7 the head 13 includes a flat top part 26 providing a form surface, a pair of lengths 27 of steel angle secured at one end to said top part 26 and at the other end to a mounting plate 28. The mounting plate 28 is formed with a hole 29 shaped for nonrotatable engagement with lugs 30 on the prop 12. The lugs 30 are used for joining the props 12 to interconnecting members 31, such joints forming the subject of British Patent No. 1,007,249. In addition the props 12 have, at their upper ends, spigots like those described in British Patent Nos. 1,006,952 and 1,127,786. The spigots 32 fit between the members 27 a short piece of tube 33 is'secured to the underside of the plate 26 between the members 27 for the purpose of locating on the top end of the spigot 32. The head 13 has a pair of brackets 34 secured respectively to the members 27 and these brackets 34 carry clamping screws 35 with their axes extending vertically.

As shown in FIGS. 1 and 2, in use, the tongues 24 on the ends of the beams 11 are clamped against the undersides of the plates 26 by means of the screws 35. The arrangement is such that the form surfaces of the beams and of the plates 26 are coplanar with the panels 10 supported by the panel-supporting elements 20. FIGS. 1 and 2 also show how panels can be made to project beyond the outermost props 12. To this end support brackets 36 of channel shaped form can be clamped to the underside of the plate 26 by means of the screws 35, each bracket 36 having a reversed flange 37 at the free end of each of its depending limbs to engage the flanges 15 of the panels. Final makeup is effected by means of plywood or similar pieces 38 supported by additional props 39. Levelling of the form surface is effected by adjustment of adjustable feet on the lower ends of the props 12 and 39 where required.

When a slab has been cast on the formwork described and the concrete has partially set the panels 10 can be removed for reuse elsewhere in the building under construction. To remove any given panel the panel-supporting element 20 at its four corners are lowered after knocking out the locking members 22 so that these drop to their lowered positions. In this condition the selected panel can be disengaged by raising one end of the panel to clear the projections 21 and sliding the other end of the panel towards the bars 19 of the adjacent beam. The edge of the panel then passes under the channel 16 of the beam and allows the first-mentioned end of the panel to become completely clear of the panel supporting elements so that it can be lowered and then removed completely from the structure. Thus removal of the panels can proceed one panel at a time in complete safety, leaving the cast slab supported by the props l2 and the beams 11. After a further setting period the beams 11 can be removed by releasing the screws 35 and removing the beams laterally from engagement with the plate 26. The slab is then supported only by the heads 13 on the props 12. Finally when the concrete is fully set the props 12 can be removed for use elsewhere.

The invention thus allows maximum utilization of equipment on a building site without the hazards normally to be encountered in this type of constructional method.

Having thus described by invention what I claim as new and desire to secure by Letters Patent is:

1. Formwork for casting concrete slab comprising the combination of a plurality of props, a plurality of heads mounted on said props respectively, each head having a form surface and means for the clamping thereto of a pair of aligned beams, a plurality of beams supported between the heads, each beam having a form surface extending throughout its entire length and coplanar with the form surfaces of the heads, a plurality of panel-supporting elements independently slidably mounted on parts of the beam at spaced positions along the length thereof, a plurality of panels supported by said panel-supporting elements and locking means for supporting said panel-supporting elements in operative positions in which the mould faces of said panels are coplanar with the form surfaces of the beams and of the heads, said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling said panels to be removed after lowering thereof from the undersurface of the cast concrete slab whilst leaving the form surface of the beam in supporting contact with the slab and the clamping means of the heads being releasable to permit removal of the beams whilst leaving the form surfaces of the heads in supporting contact with the slab.

2. An elongated beam for use in the casting of concrete slabs, said beam being adapted at its ends to be supported between props and having a form surface extending throughout its entire length, a plurality of bars extending perpendicularly to said form surface at spaced positions along the length of the beam, a plurality of panel-supporting elements independently slidably mounted on said bars, locking means for supporting said panel-supporting elements in operative positions in which panels supported by said panel-supporting elements will have their mould faces coplanar with the form surface of the beam, said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling panels supported, in use, by said panel-supporting elements to be removed after lowering thereof from the undersurface of the cast concrete slab, whilst leaving the form surface of the beam in supporting contact with the slab.

3. A beam as claimed in claim 2 in which said locking means comprises a plurality of locking plates captive on said uprights respectively and engageable with said bars to support said panel supporting elements at their opposite positions.

4. A beam as claimed in claim 3 in which each locking plate has an aperture of keyhole-shaped configuration having a narrower portion which is engageable with a groove portion of the associated bar.

5. A beam as claimed in claim 2 in which each panel-supporting element comprises a platform of a rectangular form and four projections at the corners of said platform.

6. The combination of a beam with a head for a prop, said beam being adapted at both its ends to be connected to such a head and having a form surface extending throughout its entire length, a plurality of panel-supporting elements independently slidably mounted on parts of the beam in spaced positions along the length thereof, locking means for supporting said panel-supporting elements in operative positions in which anels su orted by the panel-supporting elements will have i herr mou faces coplanar with the form surface of the beam,

said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling panels supported, in use, by said panel-supporting elements to be removed after lowering thereof from the undersurface of the cast concrete slab, whilst leaving the form surface of the beam in supporting contact with the slab, said head having a form surface alignable with the fomr surface of the beam and having means for the clamping thereto of the beam.

7. The combination claimed in claim 6 in which said form surface is provided by an upper plate on the head, said clamping means comprising a clamping screw adapted to clamp a lug on the end of the beam against the underside of said upper plate.

8. The combination claimed in claim 6 in which the head is adapted for the clamping thereto of a pair of aligned beams. 

1. Formwork for casting concrete slab comprising the combination of a plurality of props, a plurality of heads mounted on said props respectively, each head having a form surface and means for the clamping thereto of a pair of aligned beams, a plurality of beams supported between the heads, each beam having a form surface extending throughout its entire length and coplanar with the form surfaces of the heads, a plurality of panel-supporting elements independently slidably mounted on parts of the beam at spaced positions along the length thereof, a plurality of panels supported by said panel-supporting elements and locking means for supporting said panel-supporting elements in operative positions in which the mould faces of said panels are coplanar with the form surfaces of the beams and of the heads, said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling said panels to be removed after lowering thereof from the undersurface of the cast concrete slab whilst leaving the form surface of the beam in supporting contact with the slab and the clamping means of the heads being releasable to permit removal of the beams whilst leaving the form surfaces of the heads in supporting contact with the slab.
 2. An elongated beam for use in the casting of concrete slabs, said beam being adapted at its ends to be supported between props and having a form surface extending throughout its entire length, a plurality of bars extending perpendicularly to said form surface at spaced positions along the length of the beam, a plurality of panel-supporting elements independently slidably mounted on said bars, locking means for supporting said panel-supporting elements in operative positions in which panels supported by said panel-supporting elements will have their mould faces coplanar with the form surface of the beam, said locking means being releasable to permit movement of said panel-Supporting elements individually to inoperative positions enabling panels supported, in use, by said panel-supporting elements to be removed after lowering thereof from the undersurface of the cast concrete slab, whilst leaving the form surface of the beam in supporting contact with the slab.
 3. A beam as claimed in claim 2 in which said locking means comprises a plurality of locking plates captive on said uprights respectively and engageable with said bars to support said panel supporting elements at their opposite positions.
 4. A beam as claimed in claim 3 in which each locking plate has an aperture of keyhole-shaped configuration having a narrower portion which is engageable with a groove portion of the associated bar.
 5. A beam as claimed in claim 2 in which each panel-supporting element comprises a platform of a rectangular form and four projections at the corners of said platform.
 6. The combination of a beam with a head for a prop, said beam being adapted at both its ends to be connected to such a head and having a form surface extending throughout its entire length, a plurality of panel-supporting elements independently slidably mounted on parts of the beam in spaced positions along the length thereof, locking means for supporting said panel-supporting elements in operative positions in which panels supported by the panel-supporting elements will have their mould faces coplanar with the form surface of the beam, said locking means being releasable to permit movement of said panel-supporting elements individually to inoperative positions enabling panels supported, in use, by said panel-supporting elements to be removed after lowering thereof from the undersurface of the cast concrete slab, whilst leaving the form surface of the beam in supporting contact with the slab, said head having a form surface alignable with the form surface of the beam and having means for the clamping thereto of the beam.
 7. The combination claimed in claim 6 in which said form surface is provided by an upper plate on the head, said clamping means comprising a clamping screw adapted to clamp a lug on the end of the beam against the underside of said upper plate.
 8. The combination claimed in claim 6 in which the head is adapted for the clamping thereto of a pair of aligned beams. 